Driven with the understanding that I was in a hybrid luxury SUV in rush-hour traffic on I-75, the Cayenne was quite simply one of the best hybrids I've ever driven. The start/stop and coast handoff between the engine and the electric driveline was as close to seamless as I've experienced, and the Cayenne would cruise on all-electric at significantly higher speeds than I expected. The engine even shuts off at speed when the throttle is closed, but you'd never notice. On more than one occasion, I was puttering along and looked down to discover the tach at the "ready" position, gasoline engine off--and off it stayed for 22 minutes of my 38-minute commute, according to the trip computer. It was just exceptionally good at being a hybrid.

As for being a Porsche, well, the ignition switch is on the left, and there were all those shields on everything. Otherwise, it might as well have been an Audi or Volkswagen. The styling is as nondescript as ever, the handling was good but far from great, with slightly overboosted electric power steering and a more twitchy demeanor in curves than I expected. The interior has fantastic seats, far too many buttons and the ugliest steering wheel this side of a 1980 BMW. In fact, it looked a lot like the wheel in my old 320is. I can't believe we paid extra for the thing.

So my evening with the Cayenne S hybrid was rather odd. I'm surprised to find my favorite hybrid is a Porsche. But my favorite Porsche definitely isn't its hybrid SUV.

EXECUTIVE EDITOR--AUTOWEEK.COM BOB GRITZINGER: I had read and heard about all of the Cayenne S hybrid's whiz-bang technology long before I got a chance to spend a week living with the $85,000 luxury SUV while on a trip to Colorado, which was equipped like our Detroit test car. The wide range of terrain, from freeway and suburban driving to steep gravel downhills and winding high-altitude mountain roads, provided the perfect proving ground for Porsche's multiple-trick pony.

It's safe to say there's considerable difference among the vehicle's three driving modes: comfort, normal and sport. While the enthusiast in me wanted to punch up sport at every turn, over time it became evident that the less aggressive modes were, in fact, ideally suited to around-town jaunts. Comfort mode tended to be great for smoothing out freeway drives, while normal was best for quick errands, keeping the chassis reasonably responsive without jarring organs on every bump.

But once the suburbs faded in the mirror and the curvy, mountainous routes beckoned, maximum chassis control was a click away. It was a delight to run hard through the mountain twisties, braking late thanks to the vehicle's strong binders, and relying on the legendary Porsche steering response and feel to keep everything on course. I'm not so sure those riding in back were quite as appreciative, but I didn't hear much complaining either.

Three other modes proved interesting to sample: low-speed E-drive, in which the car runs like an electric golf cart; hill-descent mode, which holds the vehicle at low speed on steep grades, and sport mode, which tightens powertrain response. I'm not sure E-drive really did much--the engine fired earlier than I thought it needed to, but that might have been a side effect of altitude. Hill descent was excellent and allowed for increasing velocity merely by tapping the accelerator. Sport mode seemed to make the powertrain almost too reactive, especially considering all the wild EV and stop-start things going on at the same time.

I'll give the Porsche engineers this: I've never driven a hybrid that shut down the engine as often and at as high of speeds as the Cayenne. It was not unusual to be motoring along at 60 mph and notice the tach spring to life with a touch of throttle, though the engine engagement and disengagement was seamless. The car spends a lot of time with the engine shut down. The net effect is fairly surprising fuel economy for a 5,000-pound, 380-hp performance ute. I posted nearly 23 mpg around town, usually with each of the five seats filled, and 20 mpg on treks up above the tree line. Not bad.

Would a Cayenne Turbo be more fun? Sure, but not with the green reward, let alone the hybrid's apparent range that must be somewhere well in excess of 500 miles per tankful. The thing seemed almost diesel-like in that regard--each fuel fill came at just less than half a tank with more than 350 miles on the trip meter.

Though Porsche has been and continues to be chided for losing its sports-car way with the Cayenne, a week aboard this hybrid version shows why Porsche is selling these things as fast as it can build them and is planning additional production capacity.